Synthesis of Fine‐grained NaA‐type Zeolites from Superalkaline Solutions

Abstract

The synthesis of NaA-type zeolite from superalkaline reaction mixtures by influence on the formation-and transformation rate of the polymorphous phases according to the Ostwald step rule is discussed. The appearence time of NaA as a single crystallization product is described in dependence on the reaction conditions. The kinetics of the zeolite crystallization and the property alterations of the reaction products in dependence on the time are investigated in the pilot scale.Die Synthese .van NaA-Zeolith aus hochalkalischen Reaktionsgemischen durch gezielte Beeinflussung von Bildungs-und Transformationsgeschwindigkeit der polymorphen Phasen entsprechend der Ostwaldschen Stufenregel wird untersucht und die Existenzzeit einphasiger Kristallisationsprodukte von NaA-Zeolith in Abhangigkeit von den Reaktionsbedingungen dargestellt. Die Kinetik der NaA-Kristallisation und die Eigenschaftsiinderungen der Kristallisationsprodukte in Abhangigkeit von der Reaktionszeit werden im kleintechnischen MaRstab verfolgt.

Enclosure of Sodium Tetrahydroborate (NaBH4) in Solidified Aluminosilicate Gels and Microporous Crystalline Solids for Fuel Processing

“…Tetrahydroborate-sodalite nanoparticles were successfully synthesized even at lower temperature hydrothermal conditions (60°C) from high alkaline aluminosilicate gels and NaBH4 salt [22,23]. Preparation of basic hydrosodalite by this very simple method was first described by [53,54] during experiments on zeolite A crystallization at very low temperatures under superalkaline conditions. Fine tuning of this gel method by [55] also yielded basic-hydrosodalite nanoparticles.…”

Electrostatic Filter Ash from Silane Production as Silicate Substitute in Zeolite Chemistry

“…Therefore, FA conversion into zeolites was investigated by an energy and time efficient method under low temperature super alkaline conditions. This method was described first in the literature [18][19][20] for synthesis with gels obtained from pure chemicals. In a previous study, [16,17] this method was described as a suitable procedure for alkaline digestion of filtration residues from industrial waste water reconditioning.…”

“…Therefore 8 m NaOH was revealed, a concentration already used [18][19][20] for gel syntheses from pure chemicals at low temperature. The digestion periods 0.5 h, 1.0 h, and 1.5 h were selected to investigate of the time dependent alkaline reaction behavior of FA.…”

NaBH<sub>4</sub> Sodalites, Synthesized by Modified Methods: (1) Autothermal Synthesis and (2) Crossover Reaction from Gel to Melt Flow

“…In [14] [15] it was shown that synthesis temperature and reaction time both can be remarkably reduced under insertion of high Na 2 O concentrations of 250 g/l for zeolite synthesis from aluminosilicate gels.…”